November 7, 2012

Saber Tooth Cats And Bear Dogs In Ancient Times Learned To Share Their Prey

Your mother probably told you that it´s considered good manners to share your food, but according to new research; for large predators living 9 million years ago, sharing a food supply was a daily way of life.

"These three animals were sympatric–they inhabited the same geographic area at the same time. What they did to coexist was to avoid each other and partition the resources," said report co-author Soledad Domingo, a postdoctoral fellow from the paleontology department at the University of Michigan.

The three animals involved in the study were two types of saber-toothed cats and ancient bear-dogs, which had a dog-like head and a bear-like body and walk. Based on their findings, the researchers said that the smaller cat, Promegantereon ogygia, likely used tree cover to avoid the much larger, lion-sized Machairodus aphanistus. Meanwhile, the bear dogs hunted antelope and roamed throughout more open spaces, which slightly overlapped the felines´ habitat, according to the scientists.

Fossils of the three animals were found in the Cerro de los Batallones area near Madrid. The region is renowned for its abundant remains of mammals from the Late Miocene, about 5 to 10 million years ago. Of the nine sites located there, two contain ancient pits with an abundance of meat-eating mammal bones, likely the result of these predators leaping after prey and into tar pit traps.

"These sites offer a unique window to understand life in the past," Domingo said.

In their research, the team performed a stable carbon isotope analysis on the animals' fossilized teeth. Using a dentist's drill, they collected tooth samples from 69 specimens, including 27 saber-toothed cats and bear dogs. The rest of the teeth were found to be herbivores.

After isolating the carbon from the tooth enamel, the team used a mass spectrometer to determine the ratio of carbon 13 to carbon 12 molecules. These molecules are both present in the carbon dioxide that all plants take in during photosynthesis, but different plants make use of the isotopes in different ways. Scientists are able to determine an animal´s diet based on the presence of these plants´ isotopic signatures as they travel through the food chain.

Domingo explained that these isotopic signatures can be found in carnivores, herbivores and omnivores.

"This would be the same in your tooth enamel today," Domingo said. "If we sampled them, we could have an idea of what you eat. It's a signature that remains through time."

The latest study showed that the prey-predator relationship has lasted for millions of years and extends into today.

"The three largest mammalian predators captured prey in different portions of the habitat, as do coexisting large predators today. So even though none of the species in this 9-million year old ecosystem are still alive today (some of their descendants are), we found evidence for similar ecological interactions as in modern ecosystems," said co-author Catherine Badgley, an assistant professor of ecology and evolutionary biology at the University of Michigan.